Applicant is not aware of any prior art directed to improve the safety of saws of this class other than that on well known construction in which an upper and lower guard are positioned to surround the blades of the circle saw, the lower guard being constructed to surround the lower cutting portion of the saw and to telescope within the upper guard, surrounding it as the saw advances. The summary of the prior art is illustrated on FIG. 1.
It has been found that as the piece being cut advances along the saw and the lower guard advances to protect it, the wooden chips, lower guard and saw are inclined to jam preventing further progress of the saw and requiring release of the upper jaw. This is especially true of cutting small pieces or cutting on an incline where release of the upper guard creates a hazard. This jamming prevents movement of the piece to be cut within the lower guard. That is to say, because the lower inner guard has coextensive upright sections of differing shape at both leading and trailing edges, the workpiece can have a combination of height and end edge location that allows the workpiece to bypass contact with both leading edges of the lower guard and only make jamming contact with the trailing edge of the less upright and shorter section of the lower guard.
I have invented a device which I choose to call a "movement augmenter" which attaches to the lower guard and is positioned so that it permits movement of the lower guard and prevents jamming. The device comprised a thin cylindrical disc which attaches to the lower guard and assists in pushing the latter forward by the action of the piece being cut and releases the jamming between blade, guard and chips. This is shown separable at 12 and held in position by screws 13 through openings 13a (FIG. 3 against guard 5 or cast integral with guard 5 as shown on FIG. 5.